Ultralow-Loss Substrate-Integrated Waveguides in Alumina Ribbon Ceramic Substrates for 75–170 GHz Wireless Applications

This letter reports, for the first time, the ultralow insertion loss (IL) of substrate-integrated waveguides (SIWs) in alumina ribbon ceramic (ARC) substrate, a newly developed material technology at Corning Inc., for millimeter-wave (mm-wave) packaging applications. Demonstrated on an 80- $\mu \text{m}$ -thick ARC substrate using a semi-additive patterning (SAP) process, SIWs are fed by broadband microstrip taper transitions and characterized based on conductor-backed coplanar waveguide (CBCPW)-to-microstrip transitions and microstrip feedlines in 75–110 GHz (W-band) and 110–170 GHz (D-band), respectively. Using two-tier calibration, the average measured IL of ARC-based SIWs in W- and D-bands is extracted to be 0.13 ± 0.02 and 0.155 ± 0.01 dB/mm, respectively, showing an excellent agreement with simulated and theoretical modeling results. According to comparisons, SIWs on ARC outperform those on other substrates in terms of IL over 75–170 GHz, exhibit excellent performance, and provide easier fabrication as compared to air-filled SIWs. These first results reveal the potential of ARC substrates for the development of ultrathin, high-performance passive components and modules based on SIW technology in mm-wave frequency ranges.